Device could aid detection of nuclear materials at borders

A Swiss firm will compete for $200,000 (£129,000) of funding in London this month after developing technology that could improve efforts to catch smugglers and terrorists handling nuclear materials.

Arktis Radiation Detectors is developing equipment designed to help border-control teams to distinguish dangerous nuclear substance from natural radiation sources.

Many existing detectors used to detect illicit nuclear materials at border crossings and ports often suffer from false alarms because harmless goods such as bananas and ceramics also produce gamma radiation.

An array of four detectors being commissioned

This equipment can also struggle to detect the ’special nuclear materials’ used to make weapons, such as types of uranium and plutonium, which are only weakly radioactive and can be easily shielded from certain types of radiation detector.

Arktis’s technology, which builds on research into dark matter detection at CERN, uses tubes of compressed helium to detect the hard-to-shield high-energy ’fast’ neutrons emitted by special nuclear materials and identify their source.

‘Mostly these neutrons have to be slowed down before you can measure them,’ Arktis’s chief operating officer Mario Vogeli told The Engineer.

‘But what you’ve lost is all the primary information about the source of the neutron. We can detect fast neutrons directly without sending them through that moderating process.’

Helium is more sensitive to fast neutrons than most materials because of its atomic structure and gives out light when neutrons or gamma rays collide with helium atoms.

‘From the light pulses we can tell whether we are detecting a neutron or gamma, we can tell how much energy was deposited, we can tell where the interaction took place, and we can say when the interaction took place (with nanosecond precision),’ said Vogeli.

Clarity

Arktis has developed powerful electronic systems to read and process the energy signal, as well as using a helium purification process and specially selected materials to ensure the signal is clear.

Given that the equipment can extract much more information on the neutrons, it doesn’t need to detect as many particles as existing scanners, which have to be very sensitive in order to distinguish specific sources from background radiation.

‘We have to change the way people think about this problem,’ said Vogeli. ‘It’s not about how many neutrons you measure, it’s about the data you get out.’

Helium has been used in previous detectors, either in its common form at low temperatures to detect ionisation or using the costly He-3 isotope to detect slowed neutrons, but Arktis says this is the first scanner to measure the irradiated Helium’s light signals caused by fast neutrons.

Prototype

Arktis has developed a modular prototype version of its equipment and is currently optimising the signal quality and lifetime of the technology, a process expected to take around six months.

It then hopes to provide tailored solutions to customer governments, with more pressure tube modules needed to scan larger objects that are further away and in shorter time periods, for example, a truck driving through a border.

The company is also working with the International Atomic Energy Agency (IAEA) to measure the plutonium content of spent oxide fuel, which contains a mixture of radioactive materials.

The technology could be particularly important when dealing with nuclear materials without detailed data, such as that from illicit sources or from countries that have undergone political instability and information has been lost.

Other potential applications include detecting radiation in the oil and gas industry and medical, but the company sees the security field as the most promising sector to start with.

Competition

Arktis is hoping to beat five other start-up firms to win the Global Security Challenge run by Omni Compete, which distributes private investment and government funding to innovative companies.

The winner of the start-up funding, as well as recipients of other prizes for the security, cyber-security, energy and health sectors, will be decided at the Pitch Live expo in London on 24–25 October.

Also in the running is UK/US-based Radius Health, which has developed an X-ray source on a chip for use in more portable medical-imaging systems.